The need to confirm data, inform a dive partner of a problem, to ask questions and to give as well as receive answers is an essential and integral part of diving. Unclear communication can result in distress or even can accumulate into emergency situations. In advanced forms of diving or the overhead environment this need of precise communication is amplified. Darkness in black water, inside wrecks or caves makes the process and need of communication much more important and can complicate the means of communication.
Underwater communication is more complex in caves or inside wrecks then in open water. Simplicity and ease of understanding are essential. Standard communications have been developed for general communications but if special tasks are to be performed such as cave, reef or wreck survey teams the need to develop specialized communication for specific objectives is imminent. Lights and correct lighting are essential for talk”.
The need for communication depends on multiple factors. These would include the size of the dive team, the experience levels of each diver, visibility, environmental factors as well as questions related to the specific objective of the dive. Normally, as long as each diver’s light is visible, without erratic movements and the distance remains constant, there is no real need to communicate. As a safety factor, it is good practice to do an “ o.k. ” check periodically, even though the dive is running smoothly. It is also prudent to check more regularly when distances or depths beyond those dive team members have increased.
The best way to establish communications with a diver following you is to simply bend over and look backward between your legs. Stopping and turning around to ask a question is not the preferred method. If you are facing an oncoming current, it could push you into a reef, ceiling or wall and if the floor is covered with clay or fine sediment, stopping could increase the potential for silting. Communication signals can vary from one area to another and a review of communication is in order when diving with new team members or diving in new areas.
Slate
A slate can be used in case of total communication breakdown, however exiting the cave or wreck is preferred over a long discussion inside the overhead environment. During a discussion by slate the whole team has to stop with potential silting / zero visibility consequences, loss of line or navigation in regards on where the exit is and potential entanglement. The slate can be used for data logging such as turn pressure, time in or survey data. In emergencies such as a cut or broken line, or a lost team member a slate is very important in order to leave messages in the cave or wreck.
Light
Light signals are very effective and can be used in close quarters or large distances but a diver blinded by light is not able to communicate. It takes approximately 10 minutes for eyes to readjust to the low light environment. Depending where you are, shine your light onto floors or surfaces. When a lead diver asks a question relating to the entire dive team, do not respond until you have received the responses of the divers behind you. For example, if the lead diver wants to know if everyone is ok, pass the question back. Light position, distance and steadiness can be used to determine comfort and pace of divers in the team.
O.K. – A light motion with a simple circular motion. The simplest question-response communication is, “Are you ok?” and “Yes, I’m ok.” The best way to communicate this to simply sweep your light in a circular motion on the floor or other surface of the cave or wreck. If your buddy is ok, he or she will then give the response with a circular sweep. Light OK signals are command signals as well and must be returned with an OK signal. Failure to do so needs to be investigated. Making a fast circular motion with your light could be misunderstood. It is often interpreted as a distress / problem related signal. If you are using the circular signal as “ok”, then sweep your light slowly.
Attention – A slow moving beam close or across a team members light beam indicates “I want your attention” usually followed by hand signal communication.
Emergency – An erratic or rapid light movements indicated that there is a problem and the team member using that light signal must be immediately investigated. Be prepared to hand over the long hose regulator and commence air sharing.
TOUCH CONTACT
Another area of communication occurs when following a guide line in very limited or zero visibility when hand or light signal become useless. The divers must maintain in touch contact with each other in order to communicate and the line in order to exit. The location of where the touch contact point on the body is depends on the cave or wreck passage size and configuration. In a large passage where divers can swim side by side the diver can grab the arm of the diver in front. In passages that are small or in restrictions the contact point is moving down to the leg to allow single file swimming. A firm hold to the buddy in front should be established and clear and concise signals should be used in order for our buddy in front to clearly understand the signals. The first diver out must protect the head to prevent head injury with possible unconsciousness or head injury, the second and third diver are protecting their heads behind the shoulder of the diver in front which helps as well in the streamlining of the whole team and a more efficient exit. Touch contact signals and communication can vary from one area to another.
Stop – One firm squeeze indicates the stop of forward movement. The diver giving the signal is usually the one who is giving the forward signal again to get the team into motion. Possible mask, ear clearing, gear adjustment or buoyancy adjustment could be a reason to use that signal.
Hold – A squeeze onto the hand that is holding the line indicates a hold in the exit process. Possible mask, ear clearing, gear adjustment or buoyancy adjustment could be a reason to use that signal.
Back Up – A pull backward on the arm indicates that the team must back up a little. Possible entanglement or verification of a intersection could be a reason to use that signal.
Forward – A clear push to the front indicates the team is ready to move.
Cross over Line – The diver in front is taking the free hand/arm contact hand and puts it onto the line pushing it back to indicate cross over and space needed, a small twist of the hand toward the direction of the cross over could help to understand which way the cross over is going to be.
Entangled – The line hand signal is pushed into the hand of the team member who is holding the line. If further help is needed the free/arm contact hand could be placed onto the entanglement to indicate where help is needed.
Emergency – A shaking motion onto the arm indicates an emergency. A possible out of air situation could develop and the long hose regulator could be needed to assist in an out of air emergency. One should be prepared that the out of air diver is pulling the regulator out of the mouth and proceeding to locating and securing the secondary regulator short hose.
Hand signals
While diving most communication will be done using hand signals. While giving hand signals and illuminating your hand with the light, never shine it in another diver’s face specially when communications occur in a low light or no light environment. Always point your light down or toward your lower body illuminating your hand full or partially
COMMAND SIGNALS
OK – The OK signal is the same as used in open water but has more significance since it must be returned in the same way as given, unless there is a problem. If there is any doubt about the well being of all team members the OK must be given to verify that all members are indeed OK.
Hold – The hold signal is a closed fist shown to team members and signifies the hold or stop of the whole team. It is important that the hold signal is given back as a hold signal. The OK is not the correct response since it is not clear if the signal was understood.
Surface or Exit – When communicating that a dive is terminated this must be especially clear. The thumb up signal is used and all divers must return the signal with the same thumb up signal to acknowledge that the signal was understood, the team is to turn around and the cave or wreck is to be exited to the original entry point. The golden rule of diving is any diver can terminate the dive for any reasons, no questions asked, and no discussion. Reason may be cold, fatigue, and discomfort or as simple as thirst, hunger or enough time spend in the overhead environment and no time is wasted during exit.
OTHER COMMON HAND SIGNALS
Turn around – The turn around signal is given when a team member wishes to turn the dive and exit but does not have the urgency as of the exit signal. The turn around signal is the index finger pointed up and moved in a circular motion.
Line – The line signal is used to initiate communication about line issues. The index finger is crossed over the middle finger and used in combination with the following four signals.
Entanglement – A figure eight motion with the line signal indicating an entanglement with the line that requires the help of another team member
Reel in – A circular motion with the line signal against an open palm of the other hand, indicating that the reel and line should be brought in.
Cut – A cutting motion with index and middle finger to indicate that the line has to be cut.
TIE OFF – A CIRCULAR MOTION WITH THE LINE SIGNAL POINTING DOWN, A INDICATION THAT THIS LOCATION CAN BE USED AS A LINE TIE OFF.
Silt – A rubbing motion of the thumb against the index and middle finger indicating that silt or sediments are close by or if agitated by a team member to make him or the whole team aware that a limited or zero visibility situation is imminent.
Bubbles – A tapping motion of the index finger to the thumb indicating that bubbles can be seen and depending on the size of the bubbles the diver or team decides to turn around and leave the cave.
Small/Big – A space between index finger and thumb indicating a lot with a large space between fingers and a little with a little space between finger. Usually this sign is used in combination with the silt or bubble signal to indicate the amount of silt or bubbles observed.
Question – A bend index finger resembling a question mark. This signal is given to ask questions and can be uses in combination with other signal such as bubbles, direction and team members.
Light On – The opening of the full hand with all fingers spreading indicated that the reserve light is on. When diving in caves we should look at our teammates periodically to see if the reserve lights are on and if so they should be deactivated until needed.
Out of Air – A cut throat motion with the hand indicating that the diver is out of air. This signal is used exactly the way as in open water diving and demands immediate action. Emergency light signal should be given at the same time to alert the other team members.
Decompression – The small finger (pinky) is extended while the rest of the hand is closed in a fist.
Direction – The thump is laying flat on top of the extended fingers pointing into the direction of travel while the hand is doing a waiving motion.
NUMBERS
One to Five – With the palm toward the partner extend one finger up for one, two for two up to five fingers to indicate five.
Six to Ten – With the back of the hand toward the partner and tilted by 90 degree extend one finger for six, two for seven, three for eight, four for nine and for ten give the signal for one and a zero a given an O.K. without extending the three fingers.